The voltage converter has been widely used in power systems of electronic devices. Take a voltage converter used in a four-wire RGB lighting control system with driving capability, for example. Compared with a traditional lighting control system, the four-wire RGB lighting control system with driving capability saves a V+ wire or a GND wire, so it does not have a stable electricity output. The four-wire RGB lighting control system not only cannot have the same effect as the traditional lighting control system in voltage conversion, but also requires that the control signal output from the system should match the load, for example, a control signal with 12 V must match a load with 12 V and cannot be used to control a load with 5 V or 24 V. Similarly, a control signal with 5 V must match a load with 5 V, and a control signal with 24 V must match a load with 24 V. When a load not matching the control signal has to be used, the matched resistance should be increased to increase the consumed power, which results in waste of electricity.